taste, and is more nourishing than gelatine. The various kinds of
portable soup consist of this extractive matter in a dry state, which,
in order to be made into soup, requires only to be dissolved in water.

Gelatine, in its solid state, is a semiductile transparent substance,
without either taste or smell. --When exposed to heat, in contact with
air and water, it first swells, then fuses, and finally burns. You may
have seen the first part of this operation performed in the carpenter's
glue-pot.

CAROLINE.

But you said that gelatine had no smell, and glue has a very
disagreeable one.

MRS. B.

Glue is not pure gelatine; as it is not designed for eating, it is
prepared without attending to the state of the ingredients, which are
more or less contaminated by particles that have become putrid.

Gelatine may be precipitated from its solution in water by alcohol. --We
shall try this experiment with a glass of warm jelly. --You see that the
gelatine subsides by the union of the alcohol and the water.

EMILY.

How is it, then, that jelly is flavoured with wine, without producing
any precipitation?

MRS. B.

Because the alcohol contained in wine is already combined with water,
and other ingredients, and is therefore not at liberty to act upon the
jelly as when in its separate state. Gelatine is soluble both in acids
and in alkalies; the former, you know, are frequently used to season
jellies.

CAROLINE.

Among the combinations of gelatine we must not forget one which you
formerly mentioned; that with tannin, to form leather.

MRS. B.

True; but you must observe that leather can be produced only by gelatine
in a membranous state; for though pure gelatine and tannin will produce
a substance chemically similar to leather, yet the texture of the skin
is requisite to make it answer the useful purposes of that substance.

The next animal substance we are to examine is _albumen_; this, although
constituting a part of most of the animal compounds, is frequently found
insulated in the animal system; the white of egg, for instance, consists
almost entirely of albumen; the substance that composes the nerves, the
serum, or white part of the blood, and the curds of milk, are little
else than albumen variously modified.

In its most simple state, albumen appears in the form of a transparent
viscous fluid, possessed of no distinct taste or smell; it coagulates at
the low temperature of 165 degrees, and, when once sol